What is hidden in 3D image?

Three women go down to Mexico one night to celebrate college graduation. They get drunk and wake up in jail, only to find that they are to be executed in the morning, though none of them can remember what they did the night before.
The first one, a redhead, is strapped in the electric chair and is asked if she has any last words. She says, "I just graduated from Trinity Bible College and believe in the almighty power of God to intervene on the behalf of the innocent." They throw the switch and nothing happens. They all immediately fall to the floor on their knees, beg for forgiveness, and release her.
The second one, a brunette, is strapped in and gives her last words. "I just graduated from the Harvard School of Law and I believe in the power of justice to intervene on the part of the innocent." They throw the switch and again, nothing happens. Again they all immediately fall to their knees, beg for forgiveness and release her.
The last one, a blonde, is strapped in and says, "Well, I'm from the University of Texas and just graduated with a degree in Electrical Engineering, and I'll tell ya right now, ya'll ain't gonna electrocute nobody if you don't plug this thing in."